MAX9726
DirectDrive, Headphone Amplifier with
BassMax, I2C, Volume and Gain Control
_______________________________________________________________________________________
7
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX9726
toc15
FREQUENCY (Hz)
PSRR
(dB)
10k
1k
100
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-110
10
100k
VDD = 5V + 100mVP-P
RIN = RF = 10k
Ω
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX9726
toc16
FREQUENCY (Hz)
PSRR
(dB)
10k
1k
100
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-110
10
100k
VDD = 3.3V + 100mVP-P
RIN = RF = 10k
Ω
CROSSTALK vs. FREQUENCY
FREQUENCY (Hz)
CROSSTALK
(dB)
MAX9726
toc17
-120
-110
-100
-90
-80
-70
-60
10
100
1k
10k
100k
VIN = 1VP-P
RL = 32
Ω
G = 0dB
RIGHT TO LEFT
LEFT TO RIGHT
Typical Operating Characteristics (continued)
(VDD = SHDN = 5V, PGND = SGND = 0V, C1 = C2 = 1F, CPREG = CNREG = 1F, BM_ = 0V, RIN = 10kΩ, RF = 10kΩ, maximum vol-
ume (overall gain = 0dB), BassMax disabled. Load connected between OUT_ and PGND where specified. Outputs in phase, both
channels loaded. TA = +25°C, unless otherwise noted.) (See the Functional Diagram/Typical Operating Circuit)
CROSSTALK vs. FREQUENCY
FREQUENCY (Hz)
CROSSTALK
(dB)
MAX9726
toc18
-100
-90
-80
-70
-60
-50
-40
10
100
1k
10k
100k
VIN = 1VP-P
RL = 32
Ω
G = -10dB
LEFT TO RIGHT
RIGHT TO LEFT
BassMax FREQUENCY RESPONSE
MAX9726
toc19
FREQUENCY (Hz)
GAIN
(dB)
10k
1k
100
10
15
20
25
30
35
40
10
1
100k
R2 = 36k
Ω
C3 = 0.068
μF
R2 = 22k
Ω
C3 = 0.1
μF
R2 = 10k
Ω
C3 = 0.22
μF
R1 = 47k
Ω
RL = 32
Ω
BassMax DISABLED
OUTPUT FFT
MAX9726
toc20
FREQUENCY (kHz)
AMPLITUDE
(dBV)
15
10
5
-120
-100
-80
-60
-40
-20
0
-140
020
VIN = 100mVRMS
ATTEN = 60dB
VOUT = -60dBV
RL = 320
Ω
fIN = 1kHz
VDD = 5V
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
MAX9726
toc21
LOAD RESISTANCE (
Ω)
OUTPUT
POWER
(mW)
45
40
30
35
20
25
15
70
80
90
100
110
120
130
140
150
160
60
10
50
VDD = 5V
fIN = 1kHz
THD+N = 1%
C1 = C2 = 2.2
μF
C1 = C2 = 1
μF
C1 = C2 = 0.68
μF